Checking the impact of age and alcohol with a sample size of 6 million.

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One of the problems with cognitive and behavioral research is getting a good cross-section of the general population. Although they're convenient to work with, a couple hundred college students rarely represent the full diversity of human capability and behavior, yet that's exactly what many studies rely on. But a brain-training game may now provide access to data on scales that behavioral scientists probably never dreamed of. With a user base of over 35 million, the data obtained through the game could help us tease out very subtle effects. But as a start, a team of researchers have focused on some simpler questions: how aging and alcohol affect our ability to learn.

The software is less a game itself than a game and survey platform. Developed by a company called Lumosity, it's available on mobile platforms and through a Web interface. The platform can run a variety of games (a typical one asks users to answer math questions that appear in raindrops before they hit the ground), all with an emphasis on brain training. A few games are available for free and users can pay to get access to more advanced ones.

The scientific literature on brain training games is a bit mixed, and there's some controversy about whether the games improve mental function in general, or only those specific areas of cognition that the game focuses on. Lumosity clearly argues for the former and one of its employees pointed Ars to a number of studies that he felt validate the company's approach. What's not in doubt, however, is that it has a huge user base with over 40 million registered users. And because the Lumosity platform is flexible, it has been able to get basic demographic information from many of those users; they and others have also filled out personality profiles and other assessments.

Finally, people often play the same game multiple times, potentially over several years. This allows researchers to track both how the game affects the players' abilities to process certain information (namely, do they get better at it?) and may eventually allow some longitudinal studies of a population over time.

For now, however, the company (along with a couple of researchers at outside institutions) is simply trying to validate that its dataset gives it the sort of results that have been hinted at by other work. And two of the things Lumosity started with were sleep and booze.

A lot of the Lumosity client base has answered survey questions about how much sleep they get and how often they have a drink, so the authors correlated that with their scores on a number of tests, targeting working and spatial memory as well as simple arithmetic skills. The key thing in the work was the number of subjects: over 160,000 in two cases and 125,000 in the third.

In all tests, performance sharply increased as people got more sleep, peaking at seven hours of sleep a day. From there, things showed a more gradual decline, with people who got 10 hours of sleep scoring about the same as those who got five. A similar pattern, with a much lower threshold, was apparent when it came to alcohol intake. People who had one or two drinks a day outperformed the teetotalers, but anything above the two-drink threshold saw a drop. In order to see scores similar to those who abstained, people had to have four or five drinks a day.

From there, the researchers turned to learning by tracking people's performance on a single game over 25 iterations. In general, baseline performance dropped with increasing age. But there were distinct differences between the different types of tasks. For example, spatial and working memory seemed to decline steadily from the 20s on. Math skills decayed more slowly and didn't start until the 30s, while verbal fluency stayed stable into the 50s. This seems to largely be a result of people's ability to learn. Improvements in verbal and arithmetic skills stayed largely flat across the range from 20 to 70 years, while the two memory tests showed declines in improvements across roughly the same time.

Overall, the authors admit that the results don't tell them much about the mechanisms behind the effects they're seeing (for example, they note "the apparent cognitive advantage for those who report moderate alcohol intake may be in part due to increased social and cognitive engagement compared to those who report little or no alcohol consumption"). But it is clear that the data available via Lumosity should let people test various mechanisms on a scale that would be impossible without dragging the entire student population of several universities into a behavior lab.

To aid in this, the company has set up a group that evaluates outside research proposals and provides access to the data to any that meet its criteria. Once access to the data is granted, Lumosity takes no further part, allowing researchers to evaluate the data independently. The authors of the current paper were largely Lumosity employees, but it's possible that this will eventually be a relative rarity.